Bearing systems have been widely used to pivotably connect two components of devices, such as stators and rotors of fans. Ball bearing and sleeve bearing are two typical kinds of bearings.
A ball bearing comprises an inner ball bearing race for engaging with a central rotary shaft of a rotary component of a device and an outer ball bearing race for engaging with a stationary component of the device. A plurality of balls is arranged between the inner and outer ball bearing races. This configuration allows for rotational movement of the outer ball bearing race relative to the inner ball bearing race for rotation of the rotary component without a direct surface movement between the shaft and the bearing. A low friction exists between the balls and the inner and outer ball bearing races so that the rotary component can rotate smoothly relative to the stationary component. However, the ball bearing has a low load bearing capacity since balls contact with inner and outer ball bearing races in a point-to-point manner. Furthermore, the ball bearing has many components, i.e., the inner ball bearing race, the outer ball bearing race and a plurality of balls, which increases the cost thereof.
A sleeve bearing employs a bearing which directly and movably contacts with a rotary shaft. Lubricant is filled in a space formed between the bearing and the shaft for reducing friction therebetween. The sleeve bearing has a high load bearing capacity since the bearing contacts with the rotary shaft in a surface-to-surface manner and low cost since it employs only a bearing body. However, in working of the sleeve bearing, the lubricant is gradually lost which results in high friction being generated between the rotary shaft and the bearing and noise being generated accordingly. Furthermore, high friction between the shaft and the bearing can reduce the lift of the sleeve bearing.
For the foregoing reasons, therefore, there is a need in the art for a bearing system which overcomes the above-mentioned problems.